<?php
namespace app\index\controller;
use Think\Request;

class Tt{
    public function hello(){
    $request=Request::instance();
    $a=$request->param('a/d');
    $b=$request->param('b/d');
    $str=$request->param('c');
    dump($a);
    dump($b);
    dump($str);
    $c=$a+$b;
    echo($c);
}
}

function descstr($str){
    echo($str);
    
    $len=strlen($str); //函数返回字符串的长度：
    $newstr="\r\n";
    for($i=$len-1;$i>=0;$i--){
        $newstr.=$str[$i];
    }
    
    return $newstr;
}
$str='this is the song of sons and daughters';
echo("\r\n");
echo $res=descstr($str);
?>